Badass Bookworm: Like any prominent gunter. However, he doesn't actually work into this role until after he obtains the Copper Key.
Took a Level in Badass: From a level three user who can't even get off of the school planet of Ludus to a level ninety-nine gunter who is celebrated the world over. Also in the real world. After Art3mis breaks up with him, he throws himself into the hunt, shaves his head, drops his fat, and starts constructing an elaborate Batman Gambit to expose IOI.
Samus Is a Girl: Aech presents as male in OASIS and is known as a professional competitor, and not just in egg hunting. Meeting face to face is when Wade finally realizes Aech is a woman. They share a moment of Stunned Silence before everything just "clicks" as his mind adjusts to this revelation and they laugh together.
Sassy Black Woman: She's definitely sassy, but the fact that she's also black and female are not revealed until the end of the book.
Magic Knight: The first prominent one Wade interacts with in the OASIS.
What the Hell, Hero?: Subverted. Art3mis flies off the handle at Wade when she learns that he lied about having beaten the Tomb of Horrors Lich and thereby obtaining The Copper Key, but she's not really as angry about his dishonesty as she is about the fact that he beat the Lich on the first try when it took her five weeks. She later apologizes for blowing up and acknowledges that he was only doing what any Gunter in his place would have done.
Daito (Toshiro Yoshiaki)
Shoto's "older brother" in the OASIS, he's rather brash and irritable. He is murdered by IOI when they throw him off a balcony in his home while he is protecting Shoto as he goes for the Jade Gate.
Asian and Nerdy: Though this is not an unusual level of nerdiness for gunters.
Big Guy Fatality Syndrome: He dies protecting Shoto as he goes for the Jade Gate - both in-game which was likely to happen anyway, and in real life as IOI agents came to his house and physically threw him off a balcony.
Cool Sword: Following Daito's death, Parzival gives him a +5 Vorpal Blade Masamune.
Heroic Sacrifice: Though in his case, it's not fatal in real life, he fights Mechagodzilla in Raideen to have revenge and give his friends an opportunity to open and enter the Crystal Gate. The mech and his avatar are destroyed by the Wave Motion Gun.
We Have Reserves: Starts to kill his own men in Mechagodzilla in the finale. It doesn't matter much to him, since they're using hacked rigs, meaning each person can just find a new avatar.
Ogden "Og" Morrow (The Great And Powerful Og)
Co-creator of the OASIS and close friend of Halliday, he left Gregarious Simulation Systems some years prior to Halliday's death due to his belief that it was becoming a Lotus-Eater Machine. Halliday entrusted him with keeping the contest for the egg cheating-free, and he helps the High Five's remaining members in the finale by giving them a safe real-life place to log into the OASIS.
Screw the Rules, I Make Them!: Both Ogden's avatar can do pretty much whatever he wants, including snoop on private chat rooms. An unusual benevolent example, as Ogden is using his powers to keep an eye on the High Five so he can help them out if they need it.
James Donovan Halliday (Anorak)
Creator of the OASIS and starter of the hunt for the Egg, Halliday was a computer programming genius prior to his death. An Eccentric Millionaire, he's modeled after Howard Hughes and Richard Garriott.
Screw the Rules, I Make Them!: Even more so than Ogden's avatar. His office holds the kill switch to the OASIS itself, meaning he could end the simulation permanently at any time. He gives this power to Parzival for getting the Egg.
Virtual Ghost: Subtly hinted at. Halliday is gone but his influence is still felt very strongly in the OASIS. Wade even talks to a very advanced AI version of Halliday's avatar after obtaining the egg.
The sister of Wade's deceased mother, his aunt lives with her current boyfriend Rick and regularly pawns off Wade's possessions to pay for rent for the three of them.
Jerkass: Her only scene involves selling Wade's possessions and yelling at him.
Kick the Son of a Bitch: Deconstructed for her and her boyfriend. Even though they were jerks, Wade doesn't think they deserved to die.